li.selected{
    background-color: red;
    color: white;
}
body,a,ul,ol,li{
    margin: 0;
    padding: 0;
}
a{
    text-decoration: none;
    color: black;
}
header{
    width: 100%;
    height: 50px;
    background-color: cadetblue;
    color: white;
    text-align: center;
    font-size: 12px;
    line-height: 50px;
    position: fixed;
    top: 0;
}
header h1{
    margin: 0;
}
header img{
    height: 50px;
    position: fixed;
    top: 0;
    left: 0;
}
main{
    width: 500px;
    margin-top: 50px;
    padding: 20px;
}
h3,p{
    border-bottom: 1px solid;
    padding-bottom: 5px;
}
footer{
    height: 50px;
    width: 100%;
    background-color: cadetblue;
    position: fixed;
    bottom: 0;
    color: white;
    line-height: 50px;
}
footer ul{
    width: 800px;
    display: flex;
    justify-content: space-around;
    margin: 0 auto;
}
footer ul li{
    cursor: pointer;
    list-style-type: none;
}